replacing rear frame rails?

[tarafied1]

okay, on the Stang Fix Drag car, it has been rear-ended and it's from Texas so we have a pretty good idea who rammed the rear. :hide
Anyway, I am planning to cut out the frame rails and replace them. They are buckled over the axle and just behind the spring mounting bolt. It's not horrible but you can see the floor is crinkled where the frame starts to curve up (under rear seat) and the area where the shock holes are (over the axle).
I will attach some photos.
Buckle over axle (in this pic the front of the car is on the left):

Buckle at front of spring (in this pic, the front of the car is on the left):

Notice wrinkles in floor and over axle:

My question(s)
Should I replace the rails or have them straightened?
If I replace them, should I separate them at the torque box, or rocker panel? i.e. leave the torque box on the doner rails and cut off the torque box at the rocker on the car?

 

[tarafied1]

here are some pics of the doner frame rails...
I don't see the kink in this floor:

the area over the axle is straight:

frame rails look okay on doner:

however, it looks like it's supposed to have a buldge at the spring???

 

[Fst Blk]

Wish I could be more help, but I'm not sure how the frame rails attach at the torque boxes.

For side by side comparison :thu

Bill

 

[Fst Blk]

Here's that thread I was talking about.
http://forums.vintage-mustang.com/vinta ... ement.html

Bill

 

[tarafied1]

thanks for the link and the pics. Unfortunately for me, the Mach! guys cut the frame over the axle and just replaced the rear with new parts. The pictures of the new rails does confirm that the rails are wider at the spring mount area. Maybe I don't need to replace the whole frame rails. It just seems the floor is kinked there but maybe it's normal? The doner floor is hard to tell for sure in that area.

 

[buckeyedemon]

should you first take to a frame shop and have them pull the car back into shape? it seems that if you cut out the frame rails and then tried to replace them you might be stuck with a bunch of other metal that's been pushed in.

 

[tarafied1]

a couple PO's ago it had the left rear quarter and tail panel cut out and some one also used a dent puller on the right rear quarter. I'm not sure how bent it was or if that has already changed things.

 

[scedd]

Being a drag car that wont come back onto the street, why not just weld some reinforcement plates where needed and save the hours of welding for some other part of the project?

 

[tarafied1]

yeah, I'm just a perfectionist and it will bother me.
I found a closer picture of the repop torque plate area, i'm wondering if it's not really tweaked at the front?

 

[jtfx6552]

Looking at pictures certainly has limitations. To me the buckle at the bump stop is clear as day, and is a real issue.

From the bottom at the front of the spring looks lie a jacking or bottoming out issue to me.

The buckle in the floor on the top at the front, not sure what's going on there. In the picture it is hard to tell how big it really is.

I second the frame shop recommendation. I think they'll find that only the buckle at the bump stop is an issue, but that's really the only way to know.

 

[Sluggo]

I'm with Buckeye and JTFX, I'd get it pulled.

It could have a diamond in it. I would bet the damage extends beyond the buckle. Once you cut the old rail out you'll lose the ability to measure it properly.

 

[tarafied1]

thanks. The spring area does look like damage, maybe from a jack of something. The area over the axle is clearly buckled. I will see about taking it to a body shop and get it on a frame rack.

 

[tarafied1]

looking at the repop rails with the torque box on them and a couple pics I found online, if I were to have to replace the rails it looks like keeping the torque box on the doner rail would be best.

 

[RyanG85]

What are your future plans with the car Craig? Do you intend to keep stock suspension in the rear long term or do you have visions of back halfing it? Being a drag project, I'd do as others suggested and get it pulled and straightened on a frame rack then weld plates and gussets where needed. You can make it stronger than stock with some simple gussets and braces. Once you start racing the thing, you'll be wanting change things weekly. Don't get caught up in a concourse restoration on this thing...... :no

 

[tarafied1]

I'd prefer to back half it, but I don't have the skillz like J to fab up a 4 link and tub it out. I do know how to drill out spot welds and MIG weld it back together. I also don't have the funds to buy or pay someone to build a back half car. I figured I'd put it together relatively stock. I would like to mini tub it at least, I think I can handle that.
My 5.0 may end up with about 400 bhp if I'm lucky. Eventually I would like more but this is just going to be a "toy" since my wife doesn't want me screwing with the other 67 to make it a drag car. It has a purpose and that is cruising. This car will be track only and low (super low) budget. I have a good 5.0 slightly modified with cam and heads, I have a C4 that I will build up and use a high stall CV. I have 4.11 gears for the 9" rear axle I got from BobV. It isn't going to be super fast at first but I have never "officially" drag raced either so it will be a good start.

 

[SELLERSRODSHOP]

I'm with Buckeye and JTFX, I'd get it pulled.

It could have a diamond in it. I would bet the damage extends beyond the buckle. Once you cut the old rail out you'll lose the ability to measure it properly.

+1 thats what i would recommend too. without at least having it jigged up on a rack & measured, you don't really know whats bent & where. unibodies do really weird things when wrecked. be a shame to spend all that time cutting & welding & guess wrong...

 

[tarafied1]

I am all for taking the easy way. Will they be able to do it with no engine and some of the sheet metal already cut off? The left quarter and tail panel are not permanently attached yet.

 

[tarafied1]

I really want to go racing with a classic 67 but I can get a straight 79 Mustang Fox body for $500. My 94 HO 5.0 and the Saleen/Currie 9" I got from BobV will bolt right in. I could be racing in the spring for almost no money. Maybe building a budget 67 was not such a good idea. :char
or I could just keep pluggin and be patient. It sucks to be poor!

 

[Sluggo]

If building a drag car is out of your budget or will cause budgetary concerns then either self the project or scrap it.

Personally, I think the fox body would be a better choice. You can get that done with little outlay and put an old school paint job on it.

There's jillions of go fast bolt ons parts for foxes.

Sent from my Desire HD using Tapatalk

 

[apollard]

By the time you finish with a frame shop, welding plates, and a few other 'minor' items, you'll have spent your $500 (or more).

OTOH, maybe Scedd is right will the problems really be that large for a drag car? Can you take some measurements using the frame dimesions floating around the net? If the front / rear track is OK, for a drag car it may be fine.